Compression options In this section you can set the options for automatic compression of attachments. This option will substantially reduce bandwidth usage, since most attachments such as bitmaps, documents, spreadsheets, etc. can be reduced to up to 10 times their original file size simply by compressing them. Mail essentials compresses mails in the popular zip format, which means that anybody with 'Winzip' installed can uncompress the attachments. Furthermore, Mail essentials can make the attachments self extracting, i.e. when a recipient double-clicks on the attachment it will automatically decompress itself. To compress outbound attachments: Highlight the Compression node in the Mail essentials configuration. Right click and select properties. This brings up the Compression options dialog. Tick the option 'Compress outbound mail attachments'. The following files are excluded from compression by default (since they already include compression in the file format itself): *.zip, *.pdf, *.jpg, *.gif. If you wish to add more files or remove any, click on File Types. Exclude files from compression Tick Compress to self-executable files if you wish the attachments to be converted into self-executable files. I.e. when the recipient double-clicks on the attachment the file will decompress itself automatically. Enter the minimum amount of KB that the file should be decreased by in order to activate automatic compression in the Do not compress mail if difference between original and zipped file is less than: dialog box.